Quote from OPTIONAL777:
No, a theory would not be evidence of anything but the opinion of a scientist. It is not a scientific fact in evidence. The testimony of a scientist is not an equivalent of a scientific fact. Please, please, think man.
Some scientific tests and examinations that are not universally accepted are nevertheless generally considered reliable. Some examples are neutron activation analysis to determine the identity of goods, voiceprints to determine a person's identity, and genetic testing or DNA analysis. These types of scientific procedures may be accepted in the medical communities, but they are not so established that they may be judicially noticed as automatically valid sources of scientific evidence. They may be admitted as evidence, but only after an expert witness has testified to the validity of the test.* In determining whether to admit scientific evidence from procedures that are not universally accepted, a court must ask whether the test is reliable. A technique's reliability depends on a number of factors, including whether the technique can be or has been tested, whether it has been subjected to peer review, whether the test procedures have been published, whether the test has a margin of error and, if so, at what rate, and whether the technique, as applied, conformed to existing standards for the test (Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed. 2d 469 [1993]).
*Another expert witness can say the test is not valid. Which is exactly what happens in the court system, which is exactly what happens in the scientific community when there is not universal agreement.